Strip threading device



April 1961 R. E. BUCKHOLDT 7 2,980,411

STRIP THREADING DEVICE Filed Sept. 25, 1958 3 Sheets-Sheet 1 F s. 2 b3 VIII/III] INVENTOR.

ROBERT E. BUCKHOLDT ATTORNEY.

April 18, 1961 R. E. BUCKHOLDT STRIP THREADING DEVICE 3 Sheets-Sheet 2 Filed Sept. 25, 1958 FIG. 4

INVENTOR. ROBERT E. BUCKHOLDT ATTORNEY.

April 18, 1961 R. E. BUCKHOLDT STRIP THREADING DEVICE 3 Sheets-Sheet 3 Filed Sept. 25, 1958 INVENTOR. ROBERT E. BUCKHOLDT LK 66W ATTORNEY.

STRIP THREADING DEVICE Robert E. Buckholdt, Abington, Pa., assignor to Selas Corporation of America, Dresher, Pa., a corporation of Pennsylvania Filed Sept. 25, 1958, Ser. No. 763,267 12 Claims. (Cl. 263-3) The present invention relates to furnaces for continuously heating strip material, and. more particularly to apparatus for threading the strip through the furnace.

It is customary in the continuous. heating of strip material such as strip steel and brass, to pass the strip through the furnace in a series of vertical passes around guide rolls. At the present time when threading thev strip, sections of the furnace above and below the guide rolls are removed, and ropes or chains are lowered through the openings so made. The end of the strip is attached to the rope and drawn through the furnace. The removed sections, usually of heavy metal and refractory construction, are then replaced, and the equipment started. This is a laborious, time consuming process when starting a cold furnace in operation. It is much more diificult to accomplish when a strip break occurs in a hot furnace. Not only is a large length of strip lost, but any protective atmosphere inthe furnace is lost too. This latter means that the. strip heated before the atmosphere returns to normal is also unsatisfactory.

It is an object of the invention to provide apparatus for threading the lead end of a strip of material through a path. ltis a further, and more specific, object of the invention to provide apparatus for threading a strip of sheet metal through asfurnace. With the apparatus of the invention the threading can be accomplished even in a mufile without losing an appreciable amount of a protective atmosphere.

The apparatus of the present invention includes a chain having a strip engaging portion on the lead end thereof. The chain is forced through a guide channel following thepath that the'strip is to take. The chain and its driving mechanism are so constructed that they can be inserted through and withdrawn from a-furnace or rnuflle seal with a minimum opening of the latter.-

, The various features of novelty which characterize my invention are pointed out with particularity inthe claims annexed to.and forming. a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference shouldbe had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings;

Fig. 1 is a view, partly in section, showing the apparatus;

Fig. 2 is a view on lineZ-Z of Fig. 1;

Fig. 3 is a view on line 33 of Fig. 2;

Fig. 4 is an enlarged ,side view of the chain driving mechanism; and

Fig.5 is a view taken from the left of Fig. 4.

Referring to Fig. 1, there is shown a U-shaped furnace 1 built in accordance with conventional furnace practice and heated in some desired manner such as by direct firing, convection or electrical resistance heating. The strip 6 to be heated is guided into and through the furnace by a guide roll 2 and by rolls 3, 4, and S that are located in the upper portion thereof. The strip 6 leaves 2,980,411 Patented Apr. 18, 1.951

roll 5 and passes downwardly through the furnace, through a duct 7, and around a guide roll 8 to some point of use. The lower end of the duct and roll 8 are shown as being immersed in a quench tank 9, the liquid level of which is, above the lower end of duct 7, thus sealing the. furnace chamber. The entrance to the furnace is sealed by a seal 11 which may be of any conventional type, but which is shown herein as being a pair of flexible and resilient strips 11 that extend inwardly from the sides of the furnace, and which are biased by their natural resiliency against the sides of the strip in order to close the entrance. With this construction, the furnace chamber is closed so that any desired protective atmosphere may be maintained in the furnace chamber during the time that the strip is being heated.

In threading the strip initially through the furnace, it is, necessary to move the strip upwardly from guide roll 2 through seal 11 and around the guide rolls 3, 4, and 5 to the other leg of the furnace and downwardly around roll 8. This is accomplished by means now to be described. This means includes a chain driving mechanism 12 that is located below the entrance of the furnace and aligned with a U-shaped guide channel 13' in the furnace. chamber. This guide channel is fastened to the inner wall of the furnace and follows the path that the strip. is to follow as it travels therethrough. This guide channel extendsfrom just inside seal 11 to a point below roll 5, although it could extend to the bottom of the furnace if desired. The leading end of the strip is moved through the furnace by means of a roller chain 14- that is driven by mechanism 12 through guide channel 13. The chain may be of a conventional type including rolls 15 that are connected by links 16 and pins 17, except that every third or fourth pin extends outwardly beyond the links 16 and has on the ends thereof outboard rollers 18 of a size to be received snugly within the U-shaped guide channel 13 as shown in Fig. 2. Normally the. chain is kept ready for use in a box 19 located below roll 2, with the chain being substantially aligned with guide channel- 13. Fastened near the end of the chain that is first fed into the-furnace and projecting therefrom is .a strip engaging hook 21 to which the strip is attached and by which it is carried through the furnace.

The chain driving mechanism includes a supporting member or plate 22 that is rigidly attached to a suitable support below the entrance of the furnace. A mechanismsupporting plate 23 is guided for limited vertical movement on member 22 by means of grooved rolls 24 that are journaled on member 22, the grooves of which re, ceive the edges of plate 23. The vertical position of plate 23 with respect to member 24 is determined by a cam '25 fixed to a shaft 26 that is suitably journaled on member 22. As the cam is rotated by a handle 27, also attached to shaft 26, the cam will bear against a roll 28 on plate 23 to move plate 23 and the mechanism carried thereby between its low position of Fig. 1 and its high position of Fig. 4.

A drive sprocket 34 on plate 23 drives the chain, which is guided to andpastthis sprocket by a backing member 29, shorter opposed members 31 and 32, and a guide sprocket 33. Drive sprocket 34 is attached to a' shaft,

35 journaled in plate 23 and is driven by a gear 36 also attached to shaft 35, and-a pinion 37 that is attached to a shaft 38. Shaft 38 is rotated by a crank 39 in order to rotate sprocket 34 and thereby move the chain. Reverse rotation of sprocket 34 is prevented by a ratchet 41 at? tached to shaft 35, the teeth of which are engaged by a pawl 42. Above this sprocket and backing plates 29 and 32, is a U-shaped guide section 43 similar in gross section to guide channel 13. The HPP r end of this guide section is moved through seal 11 into engagement with,

the flared lower end 44 of guide channel 13 as plate 23' rolled steel can be used; a I v v described above, theleading end of the strip is attached directly to hook Zl onthe chain; This-procedure willbefollowed when the strip: is relatively narrow or is is raised. It will be obvious that pinion 37 can be rotated by any suitable type 'of motor instead of by hand operated crank 38, if desired;

In. the operation of the. apparatus, the leading end of. f llflwhichj is preferably ,coiled, arbiind, arnaridrel XI 19;isTrn6ved-upwardly between, the guiding por-' t'ions'ofplat gzsand into, driving connection with sprocket 34. "The leading endjof .the strip. is then brought'around, I roll 2 and attached tomemberzl, Which' is located ,afew links from the end ofchain 14. Thereafter, cranki27 is is '4 .7 t guide. These sprockets can be driven individually or,

" through grooving, by a common drive shaft; In a multiple loop furnace the weightfof the upwardly and downwardly extending sections of the chain in each loop will counterbalance each other. Because of the outboard rollers 18, the chain will pass through the guides and over rollers such as 3 and 5 with a minimum of friction, and

rotated so that .will move plate 23 and the parts carried fth'ereby including; gllidesection 43 up'wardly.

When this o c:cu'rs', the guide section will extend through s'ealQll, as sh'own'in 'Figfi4, into-engagement with the lhweriflaredend of guide"channel 1 3l Thereafter;rotationjof sprocketfiiwill force the chain and the leading e idfTof'thej strip carriedthereby through the path to he followed by the strip around the various guide ,rolls; During thistime it is prefer'red'that thestripbe fed forwardly'at 'a slow speed so that the chain will only have to support its own weight and that of 'the strip above guide roll 2; The chain is preventedfrom buckling in theguide channel bythe outboard rolls 18. which'engage the interior of guide channel13 as the chainisibeing moved*upwardly. Continued forcing of the chain, through the guidechannel will permit its leading end to fall vertically downwardly afterit'leaves the right hand end ofthe guide; This continues until the chain and strip; carried" thereby have reachedthe bottorn 'of quench tank 9.; The"chain andstrip can easily be fished around roll 8 and pulled upwardly. The strip is thendisconnected from member-21 and supplied to a take-'uproll or some machine .where it is used. .While it is possible to release ratchet 41 and withdraw the chain back through guide. channel-13, it is preferable to pull the chain on through the furnace and rewind it foruse in a boxsimilar to box 19 3 so that it; will be when necessary.

ready for rethreadingthe furnace {It will be'seen with this apparatus that the ing takingplace and .only enough to permit guide section 43fto extend therethrough. This means that a very small/amountof any atmosphere maintained in the furnace during heating will be lost. Since the threading chain is notih eld in the hot furnace during the time that the strip is being heated,it.is possible to. use a chain of relativelylow alloy content. In fact,.a chain of cold light; If the strip i sfrelatively wide GrhCaV YQh WeVer,

desirableto fasten .a leader to hook 21' and thread; the leader through th'e furnace. The'strip would attachedto the leader andpulled through the furnace ray-same apparatus thatis capable of exerting more force than canbeobtained from the chain drive. M

1 'Insome cases it may be desirable to reverse substan tially the aboveprocedureby having hook 21on the following end instead of the leading end of the chain. "When this is done,the chain is forced through the furnaceabovel After the leading end thereof has been forced "through will require only aminimum of. driving force. Therefore the main power'required'is'that necessary "to'rnove the leading end of the chain through eachiof its upwardly directed passes. This power requirement will 'not v,be much more for almultiple loop furnacethan it is for the single loop furnaceshown. ,7

The description above describes the strip as being heated directly in a furnace. I It will be apparent, however, that ifthe stripis heated in a mufile, that guide channel 13 could be fastened to the interior of a muflie as well as directly to the interiorgof the furnace .wallr .As..a matter 6f fact, fthefarran'gement shown, herein is'pa'rticularly. adapted -furuse in, muflielfurnaces; The guide. channel 13 takes uponly a small amount'of room in a 'muifle, and the chain is removed ther'efrom' during the time. that the heating is taking place. Furthermore, the guide shown weighs so little and puts so little strain 'on a muffle,

that the wall ofthe mufl lecan be. quite thin, thus increas ing heat transfer to'the strip: therein.

It should be; understood, of course,.thatiany' conven- V I tionalfend seal canbe used'in place-of the quench described herein; The'chain has'sufiicient rigidity to move throughasealat the end'of the furnace as it is descending from roller 5. If the chain is pulled'through' the furnace each time a threading. operation takes place, there is no, reason to provide special sealsat each end of the furnace whichwill permit two-way travel ther'ethro ughlv v V 7 seal at the 'entrance of the furnace is open only when actual thread- From the above description it will be seen that I have provided apparatus for threading a strip through a fur-' nace or muflie whichjis easy to operate, and is inexpensive both initially and from a maintenance point of view. 3 While in accordance with the provisions of the statutes,

I have illustrated and described the best form of embodiment of my invention now known to me, it will be ap parent to those skilled in the that changes may be made in'the form-of the apparatus disclosed without de-s parting from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of, my invention-may be used to advantage 7 without a corresponding use of other'features. j

- 'What-isclaimedis:

' F 1; Apparatus for threading a of-material tobe heated througha furnace including afurnace having a guide -roll;threin .over which the strip is to pass in a loop, a guide having a U shaped section, means attaching said guide to "a 'wall of the furnace with the guide extend-' "ingfrom the entranceof said furnace around said roll and following thepath the stripisto travel, the opening ofthez-U facing the portion of the furnacethrough which the strip to travel aichain received in saidguideand having rollers thereon engaging the':legs of 'saidU' to the furnace and been attached to a pulling device, the a a strip or a leader will be attached to the hook on the other end of'the chain. Thereafter pulling the chain by hand 7 or power cause the strip to be threaded through the :In the above loop and two passes of. the strip has been described. It

"1 be obvious, however, that the apparatus can be used with a furnace or cooling tower of any number of loops. It will only be necessary to providev a guide similar to.

guide 13 for each pass ofthefurnace which the *mflwu wu w :A drive p ke l sp qc et iwqu g h Pl d at ilog r an in ite ieach:

disclosure a furnace'with a simple said guide.

prevent V, buckling and having a, stripflen'gaging portion adjacent to one end thereof with said portion projecting.

" and o k twh lwh rs v 1 1m t sn o sa sprocket.

Whee s dsha u w llbe mq ed i to and ru h d th h. sai s idgiand rinieans. itorotate; said sprocket wheel in.

5. a direction to move said end of said chain through said path.

3. Apparatus for threading a strip through a path comprising a guide channel having the same shape as and adjacent to said path, chain driving mechanism including a sprocket and a baclc'ng member to hold a chain in engagement with said sprocket, means to mount said mechanism in front of and aligned with the entrance of said guide, means to move said mechanism on its mounting means into engagement with and retract it from the entrance of said guide, a chain adapted to be received by said guide and engaged by said sprocket to be pushed through said guide, means to drive said sprocket to push said chain through said guide, and strip engaging means carried by and adjacent to the lead end of said chain.

4. Apparatus for threading a strip to be heated through a furnace including a guide channel in the furnace, a chain to be received in said channel, said chain having rollers thereon to engage the sides of said channel to prevent buckling thereof, a support adjacent to the entrance of said channel, chain moving mechanism on said support, said mechanism including a guide portion for said chain aligned with said channel, a sprocket operative to engage and push said chain through said guide portion and said channel, means to rotate said sprocket in a direction to push said chain through said guide, means to shift said mechanism on said support from a position in Which said guide portion abuts said channel to a position retracted therefrom, and a strip engaging member projecting from said chain adjacent to the leading end thereof.

5. In combination, a furnace having an elongated chamber through which a strip is to move to be heated, a guide channel in said chamber parallel to the path the strip is to follow, a seal through which the strip moves at each end of the chamber, a chain operative to move in said guide channel, chain driving means having a guide portion projecting therefrom, means to mount said driving means adjacent to the entrance seal of said chamber with said guide portion aligned with said guide channel, means to move said drive means to extend said guide portion through said entrance seal into abutting relation with said guide channel whereby the chain driven thereby will he forced through said guide channel, and strip attaching means carried by said chain adjacent to the lead end thereof.

6. In combination, a furnace having an elongated chamber through which a strip to be heated is to travel along a fixed path, a guide channel in said chamber parallel to said path, a strip pulling means operative to be forced through said guide channel, said strip pulling means having a strip engaging portion projecting from the end thereof, mechanism located adjacent to the entrance of said chamber, said mechanism including means to engage said strip pulling means and force the same through said guide channel a seal across the entrance of said chamber between said guide channel andsaid mechanism, said mechanism including a guide portion aligned with said guide channel, and means to move said mechanism from a position in which said guide portion is outside said chamber to a position in which it extends through said seal into engagement with said guide channel thereby to direct said strip pulling means in said guide channel.

7. In combination, means forming an elongated chamber having an entrance at one end thereof, flexible seal means across said end, a guide channel extending along a path in said chamber from a point adjacent to said seal, an elongated flexible member operative to be received in and move through said guide channel, driving mechanism to force said member through said guide channel, said mechanism having a guide section adapted to engage the end of said guide channel, means to mount said mechanism beyond said end of said chamber with said guide section aligned with said guide channel, means to move said mechanism from a position in which said guide sec tion is outside said chamber to a position in which said guide section extends through said seal into engagement with said guide channel, and a strip engaging device attached to said member and projecting. outwardly from the same and said guide channel. e

8. Apparatus for threading a strip through a path comprising a guide channel extending parallel to said path on one side thereof, an elongated, flexible member to be received in said guide channel, said member being pro vided with means thereon to engage the interior of said guide channel to prevent buckling of said member, said member also being provided with a strip engaging portion projecting therefrom beyond said channel toward said path, means located adjacent to the entrance of said guide channel operable to push said member through said guide channel, and mechanism to operate said means to push whereby said flexible member will be moved along said guide channel from the entrance toward the exit thereof.

9. Apparatus for threading a strip of material through a curved path in an enclosed space which includes a guide channel extending parallel to said path, driving mechanism including a guide section, means to move said mech anism from a position in which said guide section is away from to a position in which said guide section is aligned with and engages the entrance of said guide channel, an elongated, flexible strip pulling member, said member comprising a chain having rollers thereon engaging the sides of said channel to prevent buckling thereof, sprocket means in said mechanism to engage said chain and push it through said guide section and into and through said guide channel, the strip being pulled by said chain as said chain is pushed through said path.

10. Apparatus for threading a strip through a furnace chamber having a strip path therein including a curve, a guide channel in said chamber curved to follow said path and located parallel thereto, said channel terminating at one end adjacent to the entrance of said chamber, an elongated flexible member adapted to be moved through said channel, strip pulling means on said member, 21 support in front of the entrance to said chamber, driving mechanism including means to engage said member and force it in one direction, means to mount said mechanism on said support in alignment with said channel whereby said member can be forced by said mechanism into and through said channel, a seal across the entrance of said chamber, a guide section for said member on said mechanism to direct said member, and means to move said mechanism on said support from a position in which said guide section is out of said chamber to a position in which said guide section extends through said seal into and in engagement with the end of said channel.

11. Apparatus for threading a strip through a furnace chamber including a guide channel in said chamber parallel to the path the strip is to follow, an elongated, flexible chain adapted to move through said channel, said chain having rollers thereon to engage the insides of said channel to prevent buckling thereof, a strip engaging device projecting outwardly from said chain adjacent to one end thereof and drivemechanism aligned with and adjacent to the entrance of said channel, said mechanism including a sprocket to engage said chain and means to rotate said sprocket in a direction to push said chain through said channel.

12. Apparatus to thread a flexible strip through a path comprising in combination a guide'extending parallel to said path from adjacent to the beginning thereof toward the end, a flexible strip threading member directed along said path by said guide, driving mechanism for said member located in front of the starting point of said guide, said driving mechanism engaging said member to move it, and means to operate said driving member in a 

